Comparison of Flow and Heat Transfer Distributions in a Can Combustor for Radial and Axial Swirlers Under Cold Flow Conditions

2012 ◽  
Author(s):  
Andrew Carmack ◽  
Srinath Ekkad ◽  
Yong Kim ◽  
Hee-Koo Moon ◽  
Ram Srinivasan
Keyword(s):  
Heat Transfer ◽  
Flow Conditions ◽  
Cold Flow ◽  
Flow And Heat Transfer

A Study on Flow Boiling in Microchannel With Piranha Pin Fin

2015 ◽  
Author(s):  
X. Yu ◽  
C. Woodcock ◽  
Y. Wang ◽  
J. Plawsky ◽  
Y. Peles
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Flow Boiling ◽  
Transfer Performance ◽  
Flow Conditions ◽  
Pin Fin ◽  
Flow And Heat Transfer

In this paper we reported an advanced structure, the Piranha Pin Fin (PPF), for microchannel flow boiling. Fluid flow and heat transfer performance were evaluated in detail with HFE7000 as working fluid. Surface temperature, pressure drop, heat transfer coefficient and critical heat flux (CHF) were experimentally obtained and discussed. Furthermore, microchannels with different PPF geometrical configurations were investigated. At the same time, tests for different flow conditions were conducted and analyzed. It turned out that microchannel with PPF can realize high-heat flux dissipation with reasonable pressure drop. Both flow conditions and PPF configuration played important roles for both fluid flow and heat transfer performance. This study provided useful reference for further PPF design in microchannel for flow boiling.

Roughness Effects on Flow and Heat Transfer for Additively Manufactured Channels

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Curtis K. Stimpson ◽  
Jacob C. Snyder ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Factor ◽  
Flow Conditions ◽  
Roughness Effects ◽  
Flow And Heat Transfer ◽  
Technological Advances ◽  
Rectangular Channels ◽  
Significant Augmentation ◽  
Flow Through

Recent technological advances in the field of additive manufacturing (AM), particularly with direct metal laser sintering (DMLS), have increased the potential for building gas turbine components with AM. Using the DMLS for turbine components broadens the design space and allows for increasingly small and complex geometries to be fabricated with little increase in time or cost. Challenges arise when attempting to evaluate the advantages of the DMLS for specific applications, particularly because of how little is known regarding the effects of surface roughness. This paper presents pressure drop and heat transfer results of flow through small, as produced channels that have been manufactured using the DMLS in an effort to better understand roughness. Ten different coupons made with the DMLS all having multiple rectangular channels were evaluated in this study. Measurements were collected at various flow conditions and reduced to a friction factor and a Nusselt number. Results showed significant augmentation of these parameters compared to smooth channels, particularly with the friction factor for minichannels with small hydraulic diameters. However, augmentation of Nusselt number did not increase proportionally with the augmentation of the friction factor.

Convective Flow and Heat Transfer Inside a Beta Type Stirling Engine Based on Control Volume Finite Element Method

2016 ◽  
Author(s):  
Ramla Gheith ◽  
Houda Hachem ◽  
Nessrine Zahi ◽  
Fethi Aloui ◽  
Sassi Ben Nasrallah
Keyword(s):  
Heat Transfer ◽  
Control Volume ◽  
Stirling Engine ◽  
Engine Compartment ◽  
Heat Transfer Characteristics ◽  
Cold Flow ◽  
Flow And Heat Transfer ◽  
Compression And Expansion ◽  
Instantaneous Temperature ◽  
Control Volume Finite Element

In this manuscript, a beta type Stirling engine is numerically modulated. The flow and heat transfer characteristics are finely considered in each engine compartment. The PV diagram is plotted to determine the produced work by the engine. The instantaneous temperature in compression and expansion spaces present a larger variations that recorded in all treated heat exchangers. It is observed that the porous media dumps the oscillations. The temperature evolution is plotted for 100 successive Stirling cycles in order to observe its stability in each Stirling compartments. During the first 10 cycles, the regenerator temperature is influenced by the cold flow pumped by the cooler. It reaches thermal equilibrium after only 10 cycles. From this point, the regenerator temperature undergoes a slight increase to stabilize at 1.05 * Ta.

Comparison of Flow and Heat Transfer Distributions in a Can Combustor for Radial and Axial Swirlers Under Cold Flow Conditions

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Andrew Carmack ◽  
Srinath Ekkad ◽  
Yong Kim ◽  
Hee-Koo Moon ◽  
Ram Srinivasan
Keyword(s):  
Heat Transfer ◽  
Cross Sections ◽  
Reverse Flow ◽  
Rotational Velocity ◽  
Central Area ◽  
Reynolds Numbers ◽  
Flow Conditions ◽  
Flow Core ◽  
Cold Flow ◽  
Field Geometry

A comparison study between axial and radial swirler performance in a gas turbine can combustor was conducted by investigating the correlation between combustor flow field geometry and convective heat transfer at cold flow conditions for Reynolds numbers of 50,000 and 80,000. Flow velocities were measured using particle image velocimetry (PIV) along the center axial plane and radial cross sections of the flow. It was observed that both swirlers produced a strong rotating flow with a reverse flow core. The axial swirler induced larger recirculation zones at both the backside wall and the central area as the flow exits the swirler, and created a much more uniform rotational velocity distribution. The radial swirler however, produced greater rotational velocity as well as a thicker and higher velocity reverse flow core. Wall heat transfer and temperature measurements were also taken. Peak heat transfer regions directly correspond to the location of the flow as it exits each swirler and impinges on the combustor liner wall.

Three-Dimensional Analysis of Fluid Flow and Heat Transfer in Single- and Two-Layered Micro-Channel Heat Sinks

2008 ◽  
Author(s):  
M. L.-J. Levac ◽  
H. M. Soliman ◽  
S. J. Ormiston
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Numerical Study ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Micro Channel ◽  
Flow Conditions ◽  
Flow And Heat Transfer ◽  
Computer Chips ◽  
Laminar Flow Conditions

Micro-channel heat sinks are currently at the forefront of cooling technologies for computer chips where the input heat flux is projected to exceed 100 W/cm2 [1, 2]. The quest for better heat-sink designs has produced different ideas, one of which is the idea of using multi-layered micro-channel heat sinks [3, 4]. The objectives of the present investigation were to conduct a detailed numerical study of the hydrodynamic and thermal behavior of a two-layered micro-channel heat sink and to compare the performance of the two-layered heat sink with that of a single-layered sink under laminar flow conditions.

A Comparative Study of Flow Boiling in a Microchannel With Piranha Pin Fins

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
X. Yu ◽  
C. Woodcock ◽  
Y. Wang ◽  
J. Plawsky ◽  
Y. Peles
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Flow Boiling ◽  
High Heat ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Flow Conditions ◽  
Pressure Drops ◽  
Flow And Heat Transfer ◽  
Pin Fins

In this paper, we report on the recent development of an advanced microscale heat sink, termed as piranha pin fin (PPF). A 200 μm deep microchannel embedded with PPFs was fabricated and tested. Fluid flow and heat transfer performance were evaluated with HFE7000 as the working fluid. The surface temperature, pressure drop, heat transfer coefficient, and critical heat flux (CHF) conditions were experimentally obtained and discussed. A 676 W/cm2 CHF was achieved based on the heater area and at an inlet mass flux of 2460 kg/m2 s. Microchannels with different PPF configurations were investigated and studied for different flow conditions. It was found that a microchannel with PPFs can dissipate high heat fluxes with reasonable pressure drops. Flow conditions and PPF configuration played important roles for both fluid flow and heat transfer performances. These studies extended knowledge and provided useful reference for further PPF design in microchannel for flow boiling.

scholarly journals CFD SIMULATION OF VERTICAL SEVEN-ROD BUNDLE COOLED WITH SUPERCRITICAL FREON-12

2014 ◽  
Vol 3 (01) ◽  
pp. 17-28 ◽  
Author(s):  
X. Huang ◽  
K. Podila ◽  
Y.F. Rao
Keyword(s):  
Heat Transfer ◽  
Cfd Simulation ◽  
Turbulence Models ◽  
Flow Conditions ◽  
Transfer Coefficients ◽  
Cfd Simulations ◽  
Ansys Fluent ◽  
Heat Transfer Coefficients ◽  
Rod Bundle ◽  
Flow And Heat Transfer

In this paper, a seven-rod bare bundle was simulated using ANSYS Fluent 6.3.26 to accurately predict the fluid flow and heat transfer behaviour under supercritical flow conditions. Seven turbulence models were compared to identify the appropriate model to predict the experiments performed at the Institute of Physics and Power Engineering on a vertically oriented seven-rod bare bundle cooled with supercritical Freon-12. It was found that predictions of wall temperatures and heat transfer coefficients are sensitive to the choice of turbulence model as well as to the near-wall treatment. Overall, the CFD simulations were able to predict the measured sheath temperature profiles along the length of the bundle within reasonable accuracy.

Development of Test Rigs to Investigate Fluid Flow and Heat Transfer in a Stirling Engine Heater Head

2018 ◽  
Author(s):  
Pawan Kumar Yadav ◽  
Songgang Qiu ◽  
Koji Yanaga
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Test Section ◽  
Stirling Engine ◽  
Oscillating Flow ◽  
Flow Conditions ◽  
Test Rig ◽  
Charged Fluid ◽  
Preliminary Results ◽  
Flow And Heat Transfer

To study the fluid flow and heat transfer in a Stirling Engine Heater Head (HH), two benchtop test rigs were designed and manufactured. One is to evaluate flow loss in oscillating flow conditions and another is to evaluate heat transfer in unidirectional flow conditions. The main test section-heater head, is additively manufactured; the test section also consists of an additively manufactured regenerator and a heat rejecter. For fluid flow test rig, a linear actuator from Parker generates and maintains the oscillating flow by driving a piston in sinusoidal motion. The piston is sealed against the charged fluid using Trelleborg seals. At room temperature, by varying the charge pressure, frequency, and stroke length, multiple test conditions can be achieved. For heat transfer test rig, a Gast’s high-flow, low-pressure compressed air blower is used to deliver the flow. The data acquisition (DAQ) is comprised of National Instruments’ cDAQ and modules to measure the piston’s motion in real time, pressure with Kistler’s pressure transducers, and the temperatures with OMEGA’s thermocouples, located at both the inlet and outlet of the heater head. Presented also are the testing procedures, some expected results, and the Sage outputs that will be used to check against the measured data from the test rigs, including some preliminary results. Based on the preliminary results, pressure and position curves were sinusoidal, which is expected of oscillating motions, meaning the test rig is operating well.

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